Abstract: The influence of refractivity wet term on atmospheric refraction effect is often ignored during the measurement flight data processing of partial cinetheodolites. Based on the 626 sets of radiosonde data in a certain area around the Bohai Sea in 2019, the deviation of height measurement by theodolite caused by atmospheric refraction was calculated with and without the consideration of refractivity wet term by using the ray-tracing algorithm. According to the statistics of the influence of refractivity wet term on the accuracy of height measurement at different elevation angles and different heights throughout the year, the results show that the refractivity wet term is an important source of height measurement residual errors. For the test tasks with high precision requirements for target height measurement, especially in the case of low elevation angle measurement, the influence of the refractivity wet term cannot be ignored.